Generally, in the case where an electronic member is used, heat will be generated with the operation of the electronic member. Therefore, the electronic member may have a malfunction due to the generated heat, and is provided concomitantly with a heat radiating member (e.g., heat sink) for radiating the heat generated by the electronic member.
The heat sink has a heat absorbing side through which the heat generated by the object such as the electronic member is absorbed, and a heat radiating side through which the heat having been absorbed is radiated to the exterior. In this case, it is necessary for the electronic member which generates the heat to be connected with (attached to) the heat absorbing side. As disclosed by JP05-243439A and JP05-021670A, various mounting methods are proposed to mount the heat sink to the electronic member.
According to a heat sink mounting construction disclosed in JP05-243439A, the heat sink and the electronic member which generates heat are fixed to each other by screw-engaging, in such a manner that the electronic member and the heat absorbing side of the heat sink are arranged to contact each other. In this case, the heat sink and the electronic member are screw-engaged with each other in such a manner that a coil spring is sandwiched between a nut and the heat sink, thus tightly contacting (stably and evenly) the electronic member with the heat sink.
Moreover, according to the heat sink disclosed in JP05-021670A, a semiconductor chip is directly adhered to a heat absorbing portion of the heat sink through an adhesive.
However, because the heat sink mounting construction disclosed in JP05-243439A is provided with the screw, the cost will increase due to the increase of the number of the components, a tap processing and the like of a screw hole, and the time needed in fastening the screw. Moreover, there may occur a malfunction due to forgetting to fasten the screw.
Furthermore, because the adhesive is used in the heat sink mounting construction disclosed in JP05-021670A, an exfoliation of the adhesive will occur due to the difference between the linear expansion coefficients of the heat sink and the electronic member at the adhering part. Moreover, in this case, it is difficult to verify an adhering strength and the like. Because a process for drying the adhesive is necessary after the adhering, a drying equipment is to be provided and the time is needed in drying so that the cost increases. Furthermore, because the adhesive is electrically insulating, it is difficult to provide an electrical connection for grounding the heat sink. Therefore, the use of an electrically conductive adhesive is also considered. However, in this case, it is necessary to review the selection of the adhesive material and the like to minimize the problem due to the use of the adhesive.
Moreover, in the case where the heat sink is engaged with the electronic member by press-fitting a convex member formed at the heat sink into a concave portion which is directly formed at the electronic member, there may occur facture due to pressure during the press-fitting, facture due to the linear expansion coefficient difference, facture due to creep and the like. Furthermore, in this case, the heat sink cannot be grounded.
Therefore, it is desirable that the heat sink and the electronic member can be connected with each other without increasing the cost and the grounding of the heat sink is capable.